A hydraulic displacer unit has different operating states, which can be characterized by process and state variables, such as temperature, pressure, rotational speed of a drive shaft or a pressurized medium volume flow of the displacer unit. In order to detect these variables, the displacer unit has a plurality of sensors, designated a sensor arrangement.
Laid-open specification DE 10 2005 059 564 A1 shows a hydraulic displacer unit having an abundance of separated sensors, which are arranged distributed over the displacer unit. In order to make contact with the individual sensors, a complicated cable harness is provided, a cable harness strand being needed for each sensor.
The disadvantage of this solution is that the sensors arranged in a distributed manner are susceptible to mechanical damage. In addition, the connection to the control unit via the cable harness is costly and, in the event of variants of the displacer unit, is complicated to handle. For example, each variant needs a dedicated cable harness, which represents high expenditure in terms of design, fabrication and logistics. In the event of different variants of the displacer unit, individual mechanical machining of the displacer unit itself is also needed for each variant. The expenditure is all the higher, the greater the number of sensors. For each variant of the displacer unit, individual protective devices, for example protective plates, additionally have to be designed, fabricated and mounted.
Patent specification U.S. Pat. No. 6,547,531 B1 shows a hydraulic displacer unit with which the aforementioned expenditure can be reduced. In this case, a plurality of sensors are arranged to be combined in a physically compact manner to form a sensor arrangement. The sensor arrangement occupies a very small physical section on and in the displacer unit and is surrounded by a control block for its mechanical protection.
It remains unclear how contact can be made with the multiplicity of sensors of the sensor arrangement.